Carb choice. Please help!

[narr8or 10]

I have a 1969 Mach 1, 351w, 4 barrel, FMX trans, 9 inch rear end, 3.25 gear. Stock engine, pertronix Ignitor and pertronix flamethrower.

The carb that is in there now is a Holley marked DOPF-9510-U

LIST-4548-S

 

Please forgive my ignorance about this, I am still learning. I am under the impression that the carb is pretty old and could do with updating. I have a fairly rough idle at times and a pretty loud whine when it is warmed up. I know that could be due to a leak at the gasket. Also, the choke doesn't work every time. I have read enough that I know I am potentially starting a Holley/Edelbrock/Summit debate but I am not polling. I like having low end torque and also being able to get on it at speed if needed (L.A. driving). Ips it better to have an electric choke? the car is pretty stock. I don't need a fix and forget carb but neither am I a surgeon with carbs.

Do you have any suggestions for me?

[blueblood 26]

Have a play with this Carb Selector

http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp

[LiLMike 42]

I'm partial to Edlebrock carbs. I have the same configuration as you and have a 600 cfm Edlebrock with electric choke. I will step up the cfm when I stroke it out to a 408. Just my preference.

[ashleesmach1 28]

Holley 600 vacuum secondary with or with out electric choke wud be fine for your application

[narr8or 10]

Thank you all. Great info. I was also looking at the Holley street avenger 570 cfm, any opinions on that one?

[blueblood 26]

I have the 570 Streeet avenger on my 302, which may be a bit small for your 351.

Would be ok if you were not chasing top end horsepower though.

[narr8or 10]

So a 600 is the better choice for balance between low end torque and top end horsepower?

[BigDuke6 17]

what you might want to do is send your carb to Jet Performance and have them tune it for your application. They take your cam, rear end ratio, tranny gearing, head flow, and tune your carb for your exact specs. They also replace the downleg venturis with annular boosters. These make more tq and hp compared to a downleg carb. The cost of remaking your carb would be the same as buying a new one but you get one that out of the box should require no or only minimal tuning. I had a stage III done on my Holly and my car runs like it has fuel injection.

Edited April 24, 2013 by BigDuke6

[69gmachine 15]

In southern California you don't even need a choke. Before i stroked my Windsor I ran an Autolite 600 on my 351W and loved it. It had annular boosters, and I agree with BigDuke, a well tuned carb with annular boosters is just about as close to fuel injection as a carb can get. So you have choices; I would go with a 600 cfm Holley, Summit, or Autolite with Annular boosters.

 

EDIT/// The D0PF 9510 U is an over the counter universal 450 CFM Holley. I wouldn't invest any money in trying to make it better. Just start with a 600.

Edited April 24, 2013 by 69gmachine

[tony 63C 14]

I was pondering the same decision two years ago. Finally settled on a Holley 600 with electric choke. Bolted it on right out of the box and it has run flawlessly ever since. Couldn’t be happier.

The only mod was cutting off and plugging the PCV inlet so that the stock accelerator linkage bracket could be used. The stock 351W carb spacer has the PCV inlet.

Cheers,

Tony

[BigDuke6 17]

 

EDIT/// The D0PF 9510 U is an over the counter universal 450 CFM Holley. I wouldn't invest any money in trying to make it better. Just start with a 600.

 

I think Jet can make it flow where he needs to be. I sent them a Holley 650 with downleg boosters and got back a carb that with annular boosters that flowed 770. If all he needs is a 600 cfm carb, if JET was able to find an extra 120 cfm from my carb, it can prolly squeeze an extra 150 cfm out of his current carb.

[narr8or 10]

That is great information. Thank you all. This forum is great!

[bomccorkle 12]

600 street demon would be my choice

[Flanders 47]

I've got the same engine as you, pertronixII and flamethrower2 coil, and run a 570 Holley street avenger (electric choke). Car runs great, super throttle response.

 

I haven't tried putting anything bigger on it, but haven't felt I needed to!

[Boogerschnot 12]

I have a Holley Street Avenger 670 on my 351 with a mild Edl. Performer cam and intake and I like the way it runs. It was fairly easy to tune, and has enough room to grow if (when) I decide to go back into the motor for a little more power.

[BigDuke6 17]

600 street demon would be my choice

 

Barry Grant ain't the same company since it went Bankrupt.

[sportsroof69 13]

I'd run the Street Avenger 670 on it.

[snafu 10]

I've got the same engine as you, pertronixII and flamethrower2 coil, and run a 570 Holley street avenger (electric choke). Car runs great, super throttle response.

 

I haven't tried putting anything bigger on it, but haven't felt I needed to!

 

+1 on the 570 Avenger. I have a stock 351W with 2V heads, Edelbrock Performer manifold, Pertronix and dual exhaust. The 570 Holley Avenger works great with nice throttle response as Flanders said. Starts good cold or hot which my old carb had trouble with.

 

I don't know what cfm the original 4V Autolite carbs for these engines had, but I'm pretty sure it was less than 570.

Edited April 25, 2013 by snafu

[Max Power 74]

Barry Grant ain't the same company since it went Bankrupt.

 

yeah, it's owned by Holley now.

[69gmachine 15]

I don't know what cfm the original 4V Autolite carbs for these engines had, but I'm pretty sure it was less than 570.

 

True, the Autolite 4V that came on Mustangs was a 480, but the 390 FEs came with a 600. Lots of full size Fords came with 390s and 600 Autolites. I pulled mine from a T-bird.

 

I sent them a Holley 650 with downleg boosters and got back a carb that with annular boosters that flowed 770. If all he needs is a 600 cfm carb, if JET was able to find an extra 120 cfm from my carb, it can prolly squeeze an extra 150 cfm out of his current carb.

 

The Holley 450 is a completely different body than the 650. While Jet could likely improve the flow, the bowls are side hung versus centerhung like your 650 and there are no metering blocks for the back barrels (just plates) so it will never be as tuneable. I still say it's not worth investing any more time or money in the Ford Holley given all the new carbs that are ready to just bolt on and go.

[69isfine 10]

Have a play with this Carb Selector

http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp

 

What number did you use for he redline? I used 5000 as a spitball number and the system recommended an oval track racing model with 500 cfm.

[bgnorma 10]

I bought one of those Summit carbs for my 390 and it runs and starts great. It's designed like the old Autolite carbs and doesn't seep fuel all over the manifold like the Holleys do after the gaskets get some age on them. Cheap too!